An internal combustion engine (abbreviated below as an engine) of an automobile or the like mixes fuel injected from a fuel injection device and air introduced via an intake pipe to generate a combustible gas mixture and burns the combustible gas mixture in the cylinder. It is known that the mixture state of fuel injected from the fuel injection device and air significantly affects the performance of this type of engine and, in particular, the atomization of fuel injected from the fuel injection device is an important factor governing the performance of the engine.
For example, a nozzle plate 1000 illustrated in FIG. 15 can be attached to the front end side of a valve body 1003 via a nozzle holder 1004 so as to cover a fuel injection port 1002 of a fuel injection device 1001 for a 4-valve engine. The nozzle plate 1000 introduces fuel injected from the fuel injection port 1002 to a pair of inflow holes 1005 and 1005 for branching in two directions and outflow holes 1006 and 1006 communicating with the inflow holes 1005 and 1005, turns the fuel having flowed to the outflow holes 1006 and 1006 using spiral grooves 1007 formed in the outflow holes 1006 and 1006, and injects the turning fuel into an intake pipe from blowout ports 1008 and 1008, thereby promoting the atomization of the fuel in the spray.
In addition, the nozzle plate 1000 illustrated in FIG. 15 can make the spray flow to two intake valves by setting the injection angle of the fuel as appropriate based on the ratio between the inner diameter and depth of the blowout ports 1008 (see JP-UM-B-5-44539).
However, the nozzle plate 1000 illustrated in FIG. 15 is made of metal such as stainless steel, the inflow holes 1005 need to be formed (by mechanical machining such as cutting, discharge machining, laser machining, or the like) separately from the outflow holes 1006 and the blowout ports 1008 having an inclination angle different from that of the inflow holes 1005, and the spiral grooves 1007 need to be machined in the outflow holes 1006 having a small inner diameter. Accordingly, the nozzle plate 1000 illustrated in FIG. 15 has difficulty in machining and the production cost increases.
Therefore, the invention provides a fuel injection device nozzle plate that can easily change the fuel injection direction to a desired direction and has reduced production cost.